In cased well completion or stimulation operations, it is sometimes desirable to isolate one section or zone of the well from another. This is commonly accomplished with a “bridge plug”.
It is known that certain bridge plugs may be drilled out to remove them from the well.
It is known that certain bridge plugs may be selectively activated, for example by a drop ball, introduced into the well from surface, or other plugging systems.
It is known that certain bridge plugs may be retrievable, for example by retrieval from the well bore once the stimulation operation is complete.
One typical problem with conventional retrievable bridge plugs is that debris or other materials, for example frac sand or proppant, may accumulate on the top of the plug, which may make it difficult or even impossible to latch onto the plug for retrieval. The debris or other materials, may also accumulate in the annular region between the bridge plug and the casing, and may interfere with the release of the slips or the seals or both, making retrieval of the bridge plug more difficult or even impossible.
Another typical problem with conventional retrievable bridge plugs, in a multiple zone wellbore, where multiple retrievable bridge plugs are set to isolate the respective zones, is that it may be time and labour intensive to retrieve the multiple bridge plugs, one at a time, from the wellbore.
It is, therefore, desirable to provide an improved retrievable stimulation frac plug.